Moisture management is critical to optimal wound healing. In 1962, George Winter first introduced the concept of occlusive wound dressings where he observed that the moisture promoted by polyethylene coverings enhanced the rate of epitheliazation versus the unoccluded wounds which were dry. (Winter, G. D., Formation of the Scab and the Rate of Epithelization of Superficial Wounds in the Skin of the Young Domestic Pig, Nature, 193, 293-294.)
Moist wounds tend to heal at a faster rate and leave less scarring than dry wounds. In addition, numerous controlled studies have established that a moist wound environment can facilitate cellular growth and collagen proliferation, whereas dry wound tissue can be more prone to infection, scarring, delayed healing and pain. More specifically, moisture can promote wound healing by increasing the concentration of lipid mediators, cytokines, and growth factors, which are typically present in wound fluid. Moist wounds can also reduce scab formation which permits cellular migration over the wound bed.
Excessive moisture on the other hand, is also not ideal for wound healing. For example, excessive moisture can harbor bacteria and other microbes that increase the bio-burden of the wound. In addition, wound moisture can contain cellular debris and enzymes that can irritate the wound bed and delay healing. More specifically, one issue surrounding excess wound moisture is maceration, especially of the periwound area. Maceration can be defined as the over hydration of tissue, for example, around the wound bed, due to the retention of excess moisture. (Cutting, et. al., Avoidance and Management of Peri-Wound Maceration of the Skin, Nursing Times, September 2002). Thus, maceration can cause the inhibition of cell proliferation, inflammation, and ultimately longer healing times. In addition, it has been shown by Basketter D., Gilpin G., Kuhn M., Lawrence D., Reynolds F., and Whittle E. in Patch Tests Versus Use Tests In Skin Irritation Risk Assessment, Contact Dermatitis 1998; 39(5): 252-6, that macerated skin can be more sensitive to irritants.
There is a variety of wound care devices designed to address the issues of optimal wound moisture. For dry wounds, there are transparent occlusive dressings which act to retain moisture, hydrocolloids which also act to retain moisture, and hydrogels which contain a large amount of water that helps to moisten the wound. The problem with these approaches, however, is that they can contribute too much moisture. For wounds with heavy exudate, there are a variety of foams, alginates, and absorbent materials that are designed to simply soak up wound fluid. The issue with these approaches is that once the moisture is absorbed by the wound dressing it is simply held in place next to the wound, where it can still result in maceration as the patient's body reabsorbs the exudate.
Thus, a system in which a wound dressing would channel or direct excess moisture away from the patient, while maintaining some moisture near the wound to prevent desiccation of the wound would be welcomed in the art. Therefore, it is an object of the present disclosure to provide a wound dressing that can transport liquid exudate to remote storage locations.